A year-long study was conducted in Taihu Lake with the objective of investigate the diffusive fluxes of methane（CH₄）across the sediment-water interface in different ecological zones, namely the algal bloom zone, the macrophyte zone, and the open water zone. The CH₄ concentrations in the sediment porewaters and the relevant fluxes at the sediment-water interface from different ecological zones of the lake were analyzed and evaluated. Results showed that CH₄ concentrations in porewaters increased with the sediment depth. The CH₄ concentrations in the open water zone were found significantly lower than that in the other zones. The organic carbon was identified as the key factor driving the spatial and temporal variations of CH₄. The mean diffusive fluxes of CH₄ across the sediment-water interface were 122.56±32.2, 108.75±23.8, and 3.36±0.6 µmol/（m²·d）in the algal bloom zone, the macrophyte zone, and the open water zone, respectively, with the open water zone showing the significantly lower fluxes. Seasonal variations of CH₄ fluxes were observed in the lake while the fluxes were significantly higher in the spring and the summer than the other two seasons. The regression result showed that the CH₄ flux was strongly influenced by the CH₄ concentration in the porewater and the sediment porosity. Our study also demonstrated that algal blooms and macrophyte reproductions enhanced CH₄ concentrations in porewaters and significantly increased the diffusive CH₄ fluxes across the sediment-water interface in Lake Taihu.

Based on the panel data of 2383 counties in China from 2003 to 2022, the composite system synergy model and super-efficient SBM-DEA model were initially employed to quantify the synergistic reduction of pollution and carbon emissions. Subsequently, the spatiotemporal evolution patterns of synergistic reduction of pollution and carbon emissions in counties were explored by kernel density estimation, spatial autocorrelation analysis, and standard deviation ellipse. Ultimately, the XGBoost algorithm and SHAP value interpretation algorithm were combined to identify the main influencing factors of synergistic reduction of pollution and carbon emissions. The results show that. the level of synergistic reduction of pollution and carbon emissions in Chinese counties has been gradually rising, with a marked acceleration observed after 2020. The synergistic reduction of pollution and carbon emissions exhibits a “high in the east, low in the west” pattern, accompanied by a significant spatial positive correlation. The distribution center of synergistic reduction of pollution and carbon emissions in counties generally migrates to the southeast, reflecting a north-south centripetal trend and an east-west spatial divergence. Energy intensity is the main influencing factor of synergistic reduction of pollution and carbon emissions, and has a negative impact on the synergistic reduction. Technological innovation and industrial structure generally promote the synergistic reduction. The impact of economic development, population density and financial development on the synergistic reduction shows complex nonlinear characteristics. Compared with the eastern region, the impact of energy intensity on the synergistic reduction of pollution and carbon emissions in the central and western regions is more significant.

In order to identify the pollution characteristics and carcinogenic risk of oxygenated polycyclic aromatic hydrocarbons（OPAHs）in the environmental media in the coking plants, vegetation, soil and ambient air samples were collected in JD and PF coking plants. Four species of OPAHs, including 1-acenaphthenone（1-ANO）, 9-fluorenone（9-FLU）, 9, 10-anthraquinone（9, 10-ATQ）, and benzanthrone（BZO）, were detected using gas chromatography-mass spectrometry detector（GC-MSD）. The results showed that the concentrations of Σ₄OPAHs in vegetations, soils, and ambient air in PF plant were higher than those in JD plant, respectively, and 9-FLU and 9, 10-ATQ were dominated in the environmental media in both plants. The fugacity of ambient air-soil showed that 9-FLU was in equilibrium between the air and soil, and 9, 10-ATQ released from soil into the air in PF plant. Human health risks were assessed for adults through ingestion, dermal contact and inhalation. The carcinogenic risks of OPAHs in the soils in JD and PF plants were acceptable for adults, and the carcinogenic risks of OPAHs in the ambient air in both plants were also acceptable for adults. The results provide a basis for the formulation of OPAH prevention and control measures.

The collaborative ecological governance demonstration test project in the coal gangue backfills subsidence area of a city in Shaanxi Province provided an example for this study. This research investigated the environmental pollution risks in the backfill area, where coal gangue was used as the backfill material. It analyzed the spatiotemporal laws of heavy metal leaching and migration. The variation and processes of heavy metals in the soil were simulated using Hydrus-1D.A comparison of measured values from the soil column experiment with the simulated values verified the model, and the analysis identified relationships between infiltration distances at different periods and concentration equilibrium times in various soil layers. The results demonstrated that the established model effectively simulated the migration and change patterns of heavy metals in the soil of the backfill area. Over time, the leaching concentrations of heavy metals varied with depth, ranked as Cr（Ⅵ）= Pb>Ni>Hg, with maximum migration distances of 21.60, 21.60, 20.70 and 16.20m, respectively. At different soil layer depths, the leaching concentrations of heavy metals followed the order Pb>Cr（Ⅵ）>Ni>Hg. The concentration trends increased rapidly and stabilized, with none exceeding the limit values. The findings confirmed no significant environmental pollution impacts occurred in the coal gangue backfill subsidence area.

Traditional fertilizers are prone to causing excessive nutrient levels in the soil, and nutrient loss through surface runoff, denitrification, volatilization, and leaching not only harms the environment but also affects human health. Therefore, developing fertilizers that improve nutrient utilization efficiency and reduce pollution is crucial. Slow-release fertilizers provide an effective solution to this issue by precisely controlling the release of chemical components, and biochar-based slow-release fertilizers, in particular, have attracted increasing attention due to their unique properties. Various methods to enhance fertilizer efficacy have been studied in terms of preparation and application, including co-pyrolysis, impregnation, encapsulation, and granulation, with in-depth analyses of nutrient loading and release mechanisms. In recent years, significant progress has been made in research on biochar-based slow-release fertilizers, covering aspects such as raw material selection, preparation processes, and application effectiveness. These studies have demonstrated that biochar-based slow-release fertilizers can effectively improve nutrient use efficiency and significantly reduce environmental impacts. However, challenges remain in their practical application, and further optimization of preparation processes is necessary to enable the feasibility of large-scale implementation.

To unveil the carbon release capacity of humic soil and its potential applications in wastewater treatment, this study explored the impact of various aeration gradients on the release of dissolved organic matter（DOM）from humic soil. By establishing gradients of no aeration, low aeration, medium aeration, and high aeration, the carbon release experiment lasting 600 hours was conducted. The carbon release capacity at various time points and DOM changes in components were monitored with the aid of total organic carbon（TOC）analysis, three-dimensional fluorescence spectroscopy-parallel factor analysis（EEM-PARAFAC）, and UV-visible absorption spectroscopy. Results showed that aeration intensity significantly affected the amount and cycle of carbon release from humic soil. Before reaching medium aeration, the carbon release capacity increased with the intensity of aeration, followed by a decrease afterwards. Aeration was found to enhance the release of aromatic protein-like substance I（C1）and humic-like substances（C3）. However, the intensity and effectiveness of the enhancement varied between these two components. Conversely, aeration suppressed the release of aromatic protein-like substance II（C2）and soluble microbial metabolic substances（C4）, where differences were also observed. UV-visible absorption analysis indicated that the aromaticity and humification degree of DOM increased over time during the carbon release process from humic soil. The carbon release cycle was about 248h during the 600-h test, higher aeration intensities were found to improve the microbial utilization of DOM.

In this study, we conducted a laboratory experiment to study the effects of oxygen-loaded biochar on nitrogen transformation and arsenic migration in paddy soil, and to assess the inhibition effect of oxygen-loaded biochar on arsenic migration in paddy soil-rice system. The results showed that the oxygen-loaded walnut shell biochar reduced the pH of pore water, alleviated the decline of DO and increased Eh. Meanwhile, the abundance of amoA gene in the paddy soil significantly increased（P<0.05）, which promoted the nitrification process. Also the the release of nitrous oxide was reduced and the loss of total nitrogen was depressed. After 80days, the arsenic（III）content in the paddy soil in the oxygen-loaded biochar and biochar applied treatment accounted for 42.6%、51.9%, respectively, which were significantly lower（P<0.05）than that in control（90.2%）. The amendment of oxygen-loaded biochar was also responsible for the increase in the height and tillers of rice, as well as the accumulation of iron plaque around rice root, which reached 18.4 mg/kg and was 4.2 times higher than that in control. Therefore, the arsenic content in rice was reduced by 46.3%. This indicates that the addition of oxygen-loaded biochar in paddy soil increased the concentration of iron plaque in rice roots, led to more arsenic fixation, and triggered the reduction in the accumulation of arsenic in rice. The results offer a new sight to inhibit the nitrogen loss in paddy soil and arsenic mitigation in rice.

In order to explore the community structure and construction mechanism of soil protozoa in Lhamu Lhacuo National Wetland Park, 24 large samples were set up in July 2023 according to the geographical and habitat characteristics in the study using the plum blossom five-point sampling method with a total of 120 soil samples. The culture and morphological identification of soil protozoa were performed by non-submerged culture method and in vivo observation method. The quantitative study was conducted by Petri dish direct counting method. A total of 175 soil protozoa species were identified, belonging to 12 classes, 29 orders, 55 families and 91 genera, mainly composed by species of Zoomastigophorea accounting for 15.43% of the total species, and species of Heliozoea was the least, accounting for 1.14% of the total species only. The α diversity of soil protozoa community in Lhamu Lhacuo National Wetland Park. had no significant difference between slopes（P>0.05）, and the Shannon-Wiener diversity index and Simpson dominance index at low, middle and high altitudes were significantly different from those at high altitude（P<0.05）. In the co-occurrence network analysis, the relationships between soil protozoan communities in different slope aspects and at different altitudes are mainly positively correlated. Altitude, pH value, soil water content, soil organic matter, available potassium, and vegetation coverage are the main soil environmental factors that affect the composition of soil protozoan communities. The results of this study are helpful for evaluating and monitoring the changes in the soil environmental quality of the Lhamu Lhacuo National Wetland Park, and can provide basic theoretical data for the protection of soil ecological functions and the sustainable development in the Tibet region.

To deal with problems such as high concentration of arsenic（As）and fluorine（F）in water, along with difficulty in dealing with complex pollution and irrigation utilization, zirconium-aluminum modified biochars were synthesized to study their adsorption efficiency and mechanism of As and F. The study was conducted to explore the impact of initial concentration, adsorption time, pH, and co-existing ions on their adsorption. The combination of SEM, BET, FTIR, and X-ray techniques were applied to characterize and analyze the materials. The results showed that zirconium-aluminum bimetallic modified biochar（ZA-BC）was an excellent mesoporous biochar with a good pore structure, which can rapidly adsorb As and F ions within 6hours. With initial concentrations of 1mg/L for As and 5mg/L for F, and a biochar dosage of 1g/L, As and F removal rates can reach 98.7% and 95.2%. The optimal adsorption pH of As and F by ZA-BC was 4~5, the zero charge point of the material was 9.1. Its adsorption fits the Langmuir isotherm and pseudo-second-order kinetic models within a pH range of 4.0~9.1. ZA-BC adsorbed As and F at 19.62 and 28.70mg/g, respectively, with CO₃^2- most affecting its efficiency. ZA-BC's adsorption of As involved electrostatic attraction and surface complexation, whereas for F, it's primarily electrostatic and ion exchange. The hydroxyl group was vital for adsorption, with metal modifications enhancing the immobilization of As and F via M-OH groups. Comprehensive tests had shown that ZA-BC was a promising adsorbent for removing arsenic and fluoride from water.

To investigate the feasibility of anaerobic digestion of antibiotic fermentation residues（AFR）as sole substrates, several typical AFR, including erythromycin fermentation residue（EFR）, cephalosporin fermentation residue（CFR）, and penicillin fermentation residue（PFR）were chosen as raw materials for digestion in this study. Batch assays of methane production potential and kinetics experiments were conducted at mesophilic temperature（35±1℃）to explore the basic characteristics of anaerobic digestion of different AFR. Mass balance and correlations between basic characteristics of raw materials and digestion performance were compared and contrasted. Results showed that EFR had the highest methane production potential, approximately 226mL/g VS, which was 27.0% and 20.2% higher than CFR and PFR, respectively. Distinct kinetic characteristics and metabolic activity differences were exhibited by different antibiotic fermentation residues during anaerobic fermentation. The highest biogas production rate, which was 13.2mL/（g VS·d）, was found in PFR. A clear two-stage characteristic was exhibited by EFR, with the first-order kinetic constants K₁ and K₂ being 0.0336 and 0.2012d^-1, respectively. Material balance verification confirmed the reliability of the experimental results, and the remaining insoluble substances significantly impact the startup and stability of the anaerobic system. Correlation analysis indicated that the parameters of SCOD/TCOD, C/N, protein, and fat content in the fermentation residues are important for assessing their performance in anaerobic fermentation, suggesting that optimizing the characteristics of the fermentation residues can improve fermentation efficiency. It was demonstrated that antibiotic fermentation residues treated with antibiotic removal can serve as a single substrate for anaerobic fermentation, providing a new solution for the resource utilization of fermentation residues.